NEW YORK — The price to board an airliner in the U.S. has risen for the fourth straight year, making it increasingly expensive to fly almost anywhere.

The average domestic round-trip ticket, including tax, reached $363.42 last year, up more than $7 from the prior year, according to an Associated Press analysis of travel data collected from millions of flights throughout the country. The 2 percent increase outpaced inflation, which stood at 1.5 percent.

Airfares have risen nearly 12 percent since their low in the depths of the Great Recession in 2009, when adjusted for inflation, the analysis showed.

Ticket prices have increased as airlines eliminated unprofitable routes, packed more passengers into planes, and merged with one another, providing travelers with fewer options.

Today, 84 percent of seats are filled with paying passengers, up from 82 percent in 2009.

“Anyone traveling today will know that those flights are full,” said Chuck Thackston, managing director of data and analytics for the Airlines Reporting Corp., which processes ticket transactions for airlines and travel agencies, including websites. “Just through supply and demand, those fares will go up.”

And none of this factors in the bevy of extra fees that travelers now face for checking bags, getting extra leg room or even purchasing a blanket, meal or pair of headphones. Those fees, introduced in 2008 to offset losses from rising fuel prices, now bring in $3.4 billion a year for U.S. airlines and have helped them return consistent annual profits for the past four years.

The AP reviewed data from 6 million annual flights taken in the U.S., along with fare data from Airlines Reporting Corp.